1. Field of the Invention
The invention relates to an electronic system. Particularly, the invention relates to a method and an apparatus for saving data of an electronic system.
2. Description of Related Art
With development of technology, the entire personal computer industry has developed a plurality of new specifications. The Intel, the Microsoft and the Toshiba provide the advanced configuration and power interface (ACPI) specification, which specifies a plurality of modes, between a working state and a power-off state of a computer system. And the computer system determines which specific mode to enter according to the workload, so as to save energy. The ACPI specification includes a normal working mode S0 and sleep modes of S1, S3, S4 and S5, etc. In the S0 mode, all of the devices are enabled, and in the normal working mode.
In the S3 mode, setting values of all of the devices (for example, a central processing unit (CPU), a chipset and other devices) are stored in a random access memory (RAM). When the computer system recovers to the normal working mode S0 from the S3 mode, the computer system has to set the devices such as the CPU, etc according to the setting values in the RAM. In the S3 mode, the devices enter the power-off state except for some devices using the suspend power and the RAM. In the S4 mode, the system stores the setting values of all devices onto the hard disc drive (HDD), and then the power of all devices in the computer system is off. When the computer system is going to the S0 mode from the S4 mode, the computer system has to set the devices such as the CPU, etc. with the setting values saved in the HDD.
In the normal working state, the internal devices (for example, the CPU, etc.) of the computer system heat up naturally, so that the temperature of the RAM is maintained in a normal temperature range when the computer system is in a low temperature environment. However, once the computer system enters the S3 suspend mode in the low temperature environment (for example, an environment with the temperature lower than 0 degree Celsius), the internal temperature of the computer system suddenly drops because of the suspension of the power supplied to the most of the internal devices(for example, the CPU, etc.) of the computer system. The low temperature environment may cause loss of data in the RAM. When the setting values stored in the RAM lose due to the low temperature, the computer system cannot recover to the S0 mode.